KT-4960 Redeclaration is not reported for type parameters of interfaces

When resolving a class body for a class without a primary constructor
(e.g., an interface), no checks were performed for redeclarations
in the corresponding class header.
Creating & initializing a lexical scope of an appropriate kind will do it.
Note that since class has no primary constructor, only type parameters
could be redeclared (and that's KT-4960).

idea/testData/quickfix/supercalls/typeArgumentsRedundantInSuperQualifier.kt

@@ -1,5 +1,5 @@
 // "Remove type arguments" "true"
-interface Foo<T, T> {
+interface Foo<T1, T2> {
     fun f() {}
 }
 

idea/testData/quickfix/supercalls/typeArgumentsRedundantInSuperQualifier.kt.after

@@ -1,5 +1,5 @@
 // "Remove type arguments" "true"
-interface Foo<T, T> {
+interface Foo<T1, T2> {
     fun f() {}
 }